The invention relates to a wiper system for vehicles, having at least one wiper lever assembly that has at least one wiper arm.
Wiper systems of this type are known. They are used for instance to clean the front window of a vehicle, and they include a four-bar wiper lever assembly, which has at least one wiper arm and which enables a reciprocating-pivoting motion of the wiper arm. In addition, wiper lever assemblies are known in which the wiper arm is fastened to a pivot lever that in turn is coupled in a manner fixed against relative rotation to a shaft that can be acted upon by a torque. In this version, the wiper arm is pivoted solely with the shaft, which is stationary; that is, the wiper arm does not execute any reciprocating motion.
The wiper system is mounted on the vehicle body below the front window, and the shaft with which a pivot lever that has the wiper arm is coupled in a manner fixed against relative rotation is disposed in the region of a connection point between an A pillar, an end wall, and an outer skin on the side of the vehicle body. Since this region of the vehicle body is subject to severe stress in a collision, multiple metal panels are typically provided here to stiffen the vehicle body. A hinge of an engine hood is typically mounted in this region as well. Because the vehicle body or vehicle devices limit the available space, the drivable shaft, with the pivot lever having the wiper arm and mounted on it, is disposed at a great distance from the A pillar. This arrangement means that at a turning point position of the wiper lever assembly, in which the wiper arm is located close to the A pillar, there is a great distance between the inner circle of a field swept by the wiper arm and the A pillar. This leads to an uncleaned triangular window region of the A pillar, making it harder for the driver to see.
The wiper system of the invention has the advantage over the prior art that the wiper lever assembly can be disposed at only a slight distance from an A pillar or an engine hood hinge. Because of this design, it is possible to dispose the second shaft with which the second pivot lever is connected, in the immediate vicinity of a side wall of the vehicle body in the region of the A pillar or of the engine hood hinge.
To that end, the wiper lever assembly has a first pivot lever that can be coupled in a manner fixed against relative rotation to a stationary first shaft, and also has a second pivot lever that is freely rotatably about a stationary second shaft. The second shaft is accordingly not subjected to a torque but instead serves merely to guide the pivoting motion of the second pivot lever. The first and second pivot levers are each connected in articulated fashion to a coupling element. First and second joints are provided for this purpose. The wiper system furthermore has a drive device, which has a drive shaft disposed at a distance from the first and second shafts, and with the aid of this drive shaft at least one toggle link can be shifted in oscillating fashion; the toggle link is connected via a joint to a coupling part that is coupled to the first shaft in a manner fixed against relative rotation. Thus the first shaft can be acted upon by a torque, and as a result the wiper lever assembly and accordingly the wiper arm disposed on it are pivoted accordingly. Because of this design, an optimal outset (parking) position of the wiper arm, which is located outside the field of view of a vehicle passenger, for instance, and at the same time a turning point position of the wiper lever assembly in which the wiper arm is located as parallel as possible to the A pillar, can be achieved.
In an advantageous embodiment of the wiper system, the wiper arm is fastened to the second pivot lever or joined to it. The wiper arm and the second pivot lever accordingly have the same pivot axes, which coincide with the longitudinal center (rotary) axis of the second shaft. In another variant embodiment, the wiper arm is coupled to the first pivot lever, and here the pivot axis of the wiper arm is identical to the rotary axis of the first shaft.
In a further feature of the invention, the first shaft is disposed between the drive shaft and the second shaft. This allows a disposition of the second shaft at a very close spacing from the engine hood hinge, for example, or from the A pillar and at the same time a wide spacing between the drive shaft and the second shaft. The drive shaft can accordingly be disposed more toward the middle of the vehicle. The second shaft and the drive shaft are preferably located as close together as possible, for the sake of a compact design of the bearing of the second shaft, with the aid of which the second pivot lever, and the wiper arm optionally mounted on it, can be pivoted.
A preferred exemplary embodiment of the wiper system is distinguished in that the first and second joints are embodied as ball joints. This is possible because the coupling element, which connects the first and second pivot levers to one another, transmits only the motion between the two pivot levers, and the wiper armxe2x80x94unlike the situation in the known four-bar wiper lever assembliesxe2x80x94is not disposed on the coupling element but instead is connected to one of the two pivot levers. Via the coupling elements, no moments are therefore transmitted, but only tensile and compressive forces, which can readily be withstood by ball joints without damage to the ball joints. In a variant embodiment of the wiper system, the first and second pivot levers are each provided for this purpose with a ball pin, which can be riveted on, for instance. The ball joints make it easier to put together the wiper lever assembly, since the coupling element can be clipped on in a simple way only after the mounting and optionally painting of the pivot levers and optionally the wiper arm. It is understood that it is also possible for the first and second joints to be constructed identically to the joints used in the known four-bar wiper lever assembly, but then the construction is markedly more complicated and thus more expensive than for ball joints.
In a preferred version, the rotationally fixed connection between the first pivot lever and the torque subjected first shaft is embodied separately, for instance in the form of a shaft and hub connection, cone connection, or the like. The coupling between the torque-free second shaft and the second pivot lever that is merely guided by the second shaft can also be made separable, for instance in the form of a plug-in connection.
Finally, an exemplary embodiment of the wiper system distinguished in that at least one nozzle that can be subjected to fluid under pressure is disposed on the wiper arm is preferred. The supply of fluid to the nozzle is preferably controlled such that only in an upward motion of the wiper arm, or in other words when the wiper arm is shifted out of its outset position into the viewing field of a vehicle passenger, is the fluid sprayed on the window.
Other advantageous embodiments of the wiper system will become apparent from the other dependent claims.